Pc-Bolt™

Norway

Pretec asJellestadveien 35, NO-1739 Borgenhaugen, NorwayTelephone: +47 69 10 24 60Fax: +47 69 16 71 41e-mail: post@pretec.nowww.pretec.no

SwedeN

Pre Cast Technology aBSolbräckegatan 15,SE-442 45 Kungälv, SwedenTelephone: +46 (0)303 243080e-mail: info@pretec.sewww.pretec.se

deNmark

Pretec danmark a/SÅdalen 6-12, DK-4600 KøgeDenmarkTelephone: +45 56 66 24 22Fax: +45 56 66 24 21e-mail: info@pretec.dkwww.pretec.se

FiNlaNd

Pretec Finland oy abBillskogintie 12, FI-02580 SiuntioFinlandTelephone: +358 207 345 681e-mail: info@pretec.fiwww.pretec.fi

ChiNa

Pretec ChinaNo.1-1 DanMei Road, Haining, Zhejiang province, ChinaTelephone: +86 573 87878119Fax: +86 573 87878229e-mail: tony@chinapretec.comwww.chinapretec.com

Member of:

1939ISO/TEC 17 021 Geological investigations provide an indication

of what to expect in a tunnel. When the tunnelis designed, allowances are always made for several different systems

of ground support.

Geological investigations provide an indicationof what to expect in a tunnel. When the tunnel

is designed, allowances are always made for several different systems

of ground support.

After drilling and blasting the rubble is removed, then the tun-nel walls are scaled to remove large and small rocks. Following the scaling process temporary and permanent rock support must be selected, usually this is a combination of rock bolts and shotcrete.

After drilling and blasting the rubble is removed, then the tun-nel walls are scaled to remove large and small rocks. Following the scaling process temporary and permanent rock support must be selected, usually this is a combination of rock bolts and shotcrete.

Rock support is important when excavating a tunnel. Using the Pc-Bolt™ provides an optimal result with respect to both safety and service life.

2

Independent tests show that grouting

Pc-Bolts provides an optimal result.

The drillhole is filled entirely with grout

since the bolt is grouted from

the bottom of the drillhole.

3

1 2 3 4 5 6 7

8

9

The Pc-Bolt™ is a combination bolt that has several additional benefits and functions than traditional rock bolts.

Once the bolt has been set in the drillhole, it performs imme-diately as temporary rock support. Thereafter it is grouted and performs as a fully grouted rock bolt. The bolt is easily placed in the drillhole and there are no bolt parts that would make installation difficult if there should be loose stones, poor rock etc. Even in curved drill holes, bolt installation is problem-free.

The bolt is equipped with an expansion sleeve. The sleeve is specially designed so that it will easily fasten itself to the drill-hole wall when the bolt is tensioned.

Bearing plate is designed to accommodate a large range of an-gles between the bolt and the rock wall. The domed half ball and nut distribute the forces evenly against the bearing plate.

Grouting the bolt takes place by injecting the grout to the bot-tom of the drillhole through the hollow shaft of the bolt. This ensures full grouting of the rock bolt.

Should shotcrete be applied before grouting takes place, a pro-tective cap over the bolt and an evacuation pipe for air to escape out of the hole in the spherical bearing plate are installed. Grouting can then take place after shotcrete has been applied.

Water flow in drillholes can occur. This can lead to a poor grouting result. With little or moderate water flow, the problem

The Pc-Bolt™ is supplied in 2 different versions.

Introduction

The Pc-Bolt’s design and function

Anchoring grooves at each end of the bolt. Smooth part in the middle.

Continuous anchoring grooves for reinforcement effects.

Independent testing shows that the anchoring grooves provide a significantly better anchoring capacity than a compartment on equivalent rebar designs.

4

can be efficiently solved using Tor-plug. The plug evacuates air and water but is impermeable to grout. Several plugs can be used on the same bolt. The rock character is decisive. If it is desirable to maintain pressure in the grout, a grouting valve is used.

The Pc-Bolt™ can be supplied in plain, hot dip galvanized and Pc-Coat™ versions. To achieve a long service life, the use of Pc-Coat™ is recommended. Pc-Coat™ is a Duplex system comprising hot dip galvanizing and an epoxy powder coating. Zinc-manganese phosphating is used on top of hot dip galvanizing to ensure a very strong binding of the coatings.

1 Expansion sleeve

2 Tube bolt w/grooves

3 Stem/tube bolt

4 Distancing/centring ring

5 Bearing plate w/ventilation holes

6 Domed half ball, compact

7 Nut

8 Pc-Bolt™end for grouting

9 Cavities for grout

Fittings for the Pc-Bolt™

A Pc-Bolt™ is rapid and simple

to install and fairly insensitive to poor

rock or curved drillholes.

The centring ring is an option that

ensures the bolt is placed in the centre

of the drillhole.

When grouted from the bottom of

the tube bolt, this provides an optimal

grouting result.

Protection while shotcreting after bolt installation.

In case of water leakage, we have the solution. Tor-plug stops this.

Distancing/centring ring.

Expansion sleeve.

5

The Lærdal tunnel - the world’s longest tunnel on land | Photo: The Norwegian Public Roads Administration | (illustration photo).

Areas for use of ground support

Traffic | (illustration photo).

6

The Lærdal tunnel - the world’s longest tunnel on land | Photo: The Norwegian Public Roads Administration | (illustration photo).

(illustration photo)

Subsea tunnels | Photo: The Norwegian Public Roads Administration.(illustration photo).

The Lærdal tunnel | Photo: The Norwegian Public Roads Administration (illustration photo).

7

Economy Delivery – Product advantages

The Contractor is paid to set bolts - not to install loose parts!There are many time-saving elements with the use of Pc-Bolt™.Pc-Bolt™ are delivered with the expansion sleeve already fixed and are packed in layers for easy access in a special rack attached to a pallet. This provides an easy overview and fewer parts to keep track of. The storage rack keeps the bolts in place the entire time, even after the pallet straps are cut. This results in less damage and loss when handling the bolts.

AdvantagesPc-Bolt™ makes everyday life easier for operators and cuts down the riskof errors during installation and grouting.

Bolt dimension M27 has about the same capacity whether it is temporarily end-anchored or fully grouted. Grouting provides extra corrosion protection, which ensures the service life of the bolt.

Pc-Bolt™ is easy to grout, while grouting takes place using a method that from an HSE viewpoint is very safe. Once installed, the protruding part of the bolt is minimal. This is a great advantage in cases where shotcrete, membrane and cast concrete are to be used.

Each pallet of bolts is marked with a charge number. This provides traceability for certificate 3.1 in accordance with EN10204. It is important that certificate needs be stated when ordering.

Machines at Pretec China for production of rebar bolt and Pc-Bolt™

8 9

Cold-rolled threads

Anchoring grooves

Spherical bearing plate

Evacuation hole

Domed half ball, compact

Nut

Expansion sleeve

Photo: Kjell Roger Akselsen

Fully grouted with centring ring.

Recommended drillhole Ø45–48 mm.

The white colour indicates grout that fills

the entire drillhole from the bottom up.

10

Test resultsA series of tests were performed at independent laboratories documenting the Pc-Bolt™ capacity.

Pc -Bolt™ M27 and M30 are manufactured from steel with the following characteristic values:Yield strength Rp0,2 Min. 500 N/mm2

Tensile strength Rm: Min. 600N/mm2

Ductility/Agt: Min. 10%Drillhole: Ø45–48 mmDrillhole depth: Minimum bolt length Screw threads and anchoring grooves are cold-rolled.

Pc-Bolt™ M27 has approx. the same capacity as both end-anchored and fully-grouted.Pc-Bolt™ is available er in the following lengths: M27: 1.5 m - 6.0 m M30: 3.0 m - 6.0 m

Order the product data sheet for more information.

Dimension yield strength Tensile strength Recommended torque Weight M27 157 kN 188 kN 120–130 Nm 2.52 kg/m M30 245 kN 294 kN 200-250 Nm 3.90 kg/m

Technical information

250

225

200

175

150

125

100

75

50

25

0

0 20 40 60 80 100 120 140

250

225

200

175

150

125

100

75

50

25

0

0 20 40 60 80 100 120 140

250

225

200

175

150

125

100

75

50

25

0

0 20 40 60 80 100 120 140

250

225

200

175

150

125

100

75

50

25

0

0 20 40 60 80 100 120 140

Rebar steel bolt Ø20 Load test

Rebar steel bolt Ø20 Shear test

Graph 1 Load test rebar Ø20 B500NC

Graph 3 Shear test rebar Ø20 B500NC

Graph 2 Load test M27 Pc-Bolt™

Graph 4 Shear test M27 Pc-Bolt™

Graphs 1 and 2 show a comparable load test of rebar Ø20 B500NC and M27 Pc-Bolt™.

Graphs 3 and 4 show a comparable shear test of grouted rebar Ø20 B500NC and M27 Pc-Bolt™.

Pc-Bolt™ m27 Load test

Pc-Bolt™ m27 Shear test

–––– Bolt load lengthwise (kN)

–––– Bolt load crosswise (kN)

–––– Bolt load lengthwise (kN)

–––– Bolt load crosswise (kN)

Displacement (mm)

Displacement (mm)

Displacement (mm)

Displacement (mm)Lo

ad (k

N)

Load

(kN

)

Load

(kN

)Lo

ad (k

N)

Tension Tension

Shear Shear

11

Steel

Powder Coating

Zinc Manganese phosphating

Hot dip galvanizing

From steel to treatment-finished boltThe image to the left shows the bolt’s treatment in four stages, described in the graphic illustration below.

Plain steel.

Hot dip galvanized.

Zinc manganese phosphate.

Powder-coated.

This is Pc-Coat™

12

Corrosion protection

3-layer surface Pc-Coat™The hot dip galvanizing “fuses” with the steel.Ref. NS-EN ISO 1461:2009

Zinc & manganese Phosphating provides a very strong bond with the hot dip galvanizing.

In addition, powder coatingbonds extremely well to the phosphate.Ref. NS-EN 13438:2006

The service life of the duplex system A duplex system has a much longer service life than the combined total service life of each individual coating. Tests show that the system’s service life can be calculated with the following formula: LT=K(LZn+LM).

LT = Duplex-system’s service life in yearsLZn = Zinc coating’s service life in the specific environment and with hot dip galvanizing alone.Lm = Powder coating’s calculated service life if applied directly to steel.K = Environmentally dependent synergy effects with a value that is set to:

1.5 when the system is exposed to environment class C4 and C5 or is permanently immersed in seawater.

1.6-2.0 for exposure to environment class C3 or when the system is moist at least 60% of the time.

2.1-2.3 when exposed to environment class C2.

Zinc & manganese phosphate (surface strongly magnified) 13

Grouting and equipment

The grouting nozzle is fastenedto the bolt end with onlythree threads.

The grout is forced through the inner part of the entire bolt.

Grouting valve.

Attaching the rapid connection – ready for grouting.

Tor-plug.

Full grouting is observed through the hole in the bearing plate.

InstallationPc-Bolt™ is set in a drillhole (Ø45–48 mm) with its expansion sleeve fixed. Bearing plate, domed half ball and nut are mounted before final placing of the bolt. The spherical bearing plate is formed so that it accommodates a large range of angles against the rock wall. It is important that the bolt is tensioned to the specified torque. Proper consistency of the grout - water-cement ratio: 0.39-0.41.

The Pc-Bolt’s unique design with grouting from the end of the bolt provides full grouting from the bottom of the drillhole. It is important to ensure that grout of the correct consistency is used.

Additional equipmentTo solve problems of water intrusion into the drillhole and thus the risk of grout running out, the Tor-plug and grouting valve have been developed.

14

Pc-Bolt™/combination bolt 100% grouted.Test performed by 3. part.

Independent tests have shown that the Pc-Bolt’s grouting results are optimal. The drillhole is completely filled because grout is forced from the bottom of the hole and out.

1) Drillhole. 2) Pre-tensioning the bolt.

5) Grouting the bolt is finished when the grout comes out of the hole in the spherical bearing plate or from between the rock and the bearing plate.

3) Grout exits from the bottom of the drillhole.

4) Grout fills the entire drillhole.

15

Referenceprojects

References & third party reports

- Will be sent on request

- Trial grouting using the CaviMeter method- Opinion prepared by FAVEO- SINTEF, shear testing of Pc-Bolt™- Inspecta report J-830 - Load test- Inspecta report 75890 - Load test- Swedish surface test Swerea KIMAB- Jotun ASTM 117 test, 1000h.

Range of other bolts:- Rebar bolt fully grouted- Rebar bolt end-anchored- Rebar bolt with expansion sleeve- Round steel bolt with expansion sleeve- Dynamic bolt

A complete product programme for rock support and water and frost protection of tunnels is available on our website.

16

Pretec, China.

www.pretec.noEnglish edition - October 2013 | Graphic production: Danders Grafiske, Sarpsborg